Opioid-Free Anaesthesia Improves Anaesthesia Recovery when Compared with that of Opioid-Based Anaesthesia. Systematic Review and Meta-Analysis of Clinical Trials.

INTRODUCTION: Opioid Free Anesthesia (OFA) is a relatively new technique that has been questioned due to the lack of evidence regarding its benefit-risk balance. METHODS: Four international databases were searched for clinical trials comparing OFA with opioid based anesthesia. The primary outcome was pain control and the secondary included postoperative nausea and vomiting (PONV), gastrointestinal recovery, respiratory depression, urinary retention, length of hospital stay, surgical complications, number of patients with cessation of the intervention and other side effects. RESULTS: Pain was better controlled in the OFA group in all the measurements made (VAS 1h: Md = -0.81, CI95% = -0.48- -1.14, VAS 24h: Md = -1.25, CI95% =-2.41- -0.1, VAS >24h: Md = -1.36, CI95% = -1.73- -1). In the opioid group there was an increase in the risk of nausea (RR=2.69, CI95% = 2-3.61) and vomiting (RR = 3.99, CI95% = 2.06-7.74), whilst in the OFA group, there was an increased risk of bradycardia (RR= 1.62, CI95% = 1.02-2.57). The rest of the variables showed no differences between groups or could not be analyzed. CONCLUSION: There is a clear benefit of OFA in pain control and PONV, but there is also a higher risk of bradycardia. This technique should be considered in patients with a special risk of difficult postoperative pain control or PONV. However, the best drug combination to perform OFA is still unknown, as well as the type of patient that benefits more with less risk.

Anesthesia in Combination with Propofol Increases Disease-Free Survival in Bladder Cancer Patients Who Undergo Radical Tumor Cystectomy as Compared to Inhalational Anesthetics and Opiate-Based Analgesia.

BACKGROUND: The effect of anesthetic techniques on cancer recurrence has been the subject of intensive research in the past years, as it affects a large proportion of the population. The use of opioids and halogenated agents in cancer patients during the perioperative period may be related to higher rates of cancer recurrence and reduced disease-free survival. METHODS: This was a prospective study. The sample was composed of 100 patients who underwent a radical cystectomy for infiltrating bladder cancer in a reference center. We compared disease-free survival associated with combined anesthesia versus opiate-based analgesia. The relationship between the administered hypnotic and disease-free survival was also investigated. RESULTS: The median disease-free survival of the patients who received combined anesthesia was 585 (240-1,005) days versus 210 (90-645) days in the other group. A significant difference was observed between the two groups (p = 0.01). Combined analysis of all groups revealed significant differences in disease-free survival between patients who received combined anesthesia with propofol (510 [315-1,545] disease-free days) and those who received sevoflurane and opioids (150 [90-450] disease-free days) (p = 0.02). CONCLUSIONS: Anesthesia may play a crucial role in tumor relapse, as it is administered at the moment of the greatest risk of dissemination: surgical handling of the tumor. Opioids and volatile agents have been related to an increased risk for cancer recurrence. We compared the use of propofol + local anesthesia versus sevoflurane + opioids and also found that disease-free survival was longer among patients who received propofol + local anesthesia. Disease-free survival increases with the use of propofol in combination with epidural anesthesia in patients who undergo surgery for infiltrating bladder cancer.